This API was supposed to be turned off two years ago, so no promises it will work for you.

auto_suggest

#!/usr/bin/env ruby

require 'json'
require 'yaml'

class AutoSuggest

  def self.call(*args)
    new(*args).call
  end

  attr_reader :term

  def initialize(term)
    @term = term
  end

  def cmd
    @cmd ||= <<-CMD
      curl -G --data-urlencode "q=#{term}" --data-urlencode "client=chrome" http://suggestqueries.google.com/complete/search
    CMD
  end

  def result
    @result ||= `#{cmd}`
  end

  def list
    @list ||= JSON.parse(result) rescue []
  end

  def returned_term
    @returned_term ||= list[0]
  end

  def suggestions
    @suggestions ||= list[1]
    @suggestions ||= []
  end

  def meta
    @meta ||= list[4]
    @meta ||= {}
  end

  def relevance
    @relevance ||= meta.fetch("google:suggestrelevance", [])
  end

  def types
    @types ||= meta.fetch("google:suggesttype", [])
  end

  def object
    @object ||= {
      "term" => returned_term,
      "suggestions" => suggestions,
      "relevance" => suggestions.zip(relevance),
      "types" => suggestions.zip(types)
    }
  end

  def yaml
    @yaml ||= YAML.dump(object)
  end

  def call
    yaml
  end
end

if __FILE__ == $0
  puts AutoSuggest.call(ARGV[0])
end